Automatic processing apparatus are known in which a processing rack defines a simple track along which the material being processed is driven in a simple loop. However, this simple track must have a path length which is sufficient to accommodate at least the length of the material to be processed without the material overlapping itself. This, in turn, dictates the minimum height of the processing rack and hence the overall size of the processing apparatus of which the rack forms a part.
In known processing apparatus, the track length is approximately 2 m giving a minimum overall height of around 1 m. This has the disadvantage that it is difficult to remove the processing rack from the apparatus for maintenance and repair.